Is knowledge something singular and unique, unlike any other epistemic state? Or is it possible to distinguish kinds of epistemic success, for example, by differentiating cases in which a subject knows how to execute a task from cases in which she knows that certain propositions are true? Anti-intellectualists have traditionally argued that the two are distinct, that one can know how to bring about an outcome without having the corresponding propositional knowledge. Fifteen years ago, Stanley and Williamson (2001) revived the intellectualist position, arguing to the contrary that knowledge must be propositional. In a growing literature, intellectualists have alleged that in cases in which it seems that an agent merely knows how to perform a task, the agent in fact draws on implicit or explicit propositional knowledge (e.g. Stanley 2011). According to this now popular view, knowing how can be reduced to knowing that.
In this paper we argue, against the intellectualists, that there is a distinctive kind of non-propositional knowing. Our argument depends on a simple methodological principle: If a distinction among epistemic kinds offers fruitful descriptions of performances and behaviors, then that is prima facie reason to accept it. This principle of fruitfulness entails that if knowing how explains empirical phenomena more directly and clearly than the intellectualist alternative, then we should embrace anti-intellectualism. After introducing this methodological principle in the first section, we consider two empirical cases in which knowing how decisively offers a more fruitful description than the intellectualist alternative. The first case is the ability of amnesiacs to master predictive tasks. The second case is that of reduplicated babbling in infants, a kind of behavior that can be described as knowing how to produce syllables. In the final section we argue that, in the absence of more fruitful alternative explanations, we should accept the distinction between knowing how and knowing that. Though some intellectualists have pursued the strategy of deflating the concept of “propositional knowledge” to include cases in which one is not only unaware of but in principle lacks access to the relevant proposition, this has little explanatory value in the cases we consider. While intellectualists are committed to describing all cases of skill as exercises of implicit knowledge of a proposition, we think that there are important distinctions to be made among non-epistemic acuity, knowledge how, implicit propositional knowledge that, and explicit knowledge of a proposition. By considering cases in which knowledge how can be reduced neither to acuity nor to implicit propositional knowledge, we offer philosophers and psychologists a way of ascribing knowledge that clarifies rather than obscures empirical phenomena.